Contemporary Asia in the World. New York: Columbia University Press, 2017. x, 259 pp. US$30.00, paper. ISBN 978-0-231-15799-5 .
Terence Roehrig has written a lucid and sophisticated book on US-extended nuclear deterrence in East Asia that experts and students alike will find insightful. True to the book’s name, Roehrig examines the past and present of the proverbial nuclear umbrella that the United States has extended to Japan and South Korea since the early 1950s. Evidently written before the surprise election victory of Donald Trump, Roehrig wagers that these alliance commitments will continue to rest on a sound foundation in the foreseeable future. In fact, as he argues, the United States need not resort to nuclear weapons to be militarily and political credible in any armed crisis. So long as it possesses conventional weapons capable of “strategic effects similar to nuclear weapons,” its nuclear umbrella will be robust enough to discourage not only large-scale aggression by adversaries like China and North Korea, but also nuclear proliferation by these allies (190).
This book has not been overtaken by events. Despite Trump’s declared intent to put “America First,” the alliance treaties with South Korea and Japan are still in the books and the military foundations of the nuclear umbrella remain unchanged. Over 23,000 US military personnel and their families are currently stationed in South Korea. Another 50,000 US military personnel and their facilities are in Japan. As my own research reveals, and which Roehrig appears to corroborate, these military deployments have been crucial for not only conveying how the United States has skin in the game when it comes to the defence of their allies, but also the credible wherewithal to fight would-be aggressors to at least a hurting stalemate (Lanoszka, Atomic Assurance: The Alliance Politics of Nuclear Prolfieration, Cornell University Press, 2018). Nuclear deterrence relies on conventional deterrence, and so—as far as military power is concerned—the changes to the overall security environment since 2016 may be less than what people think (179–180).
An awareness that these operational continuities exist should not invite nonchalance regarding how Trump has been treating US allies, not least among them South Korea. Much of the rhetoric from the White House has been corrosive, further deepening concerns that have been percolating since at least 2008 over whether the United States can be trusted to defend far-flung allies against nuclear-armed adversaries. Still, the experience of the Trump presidency so far offers us an opportunity to reflect on some of the quirks of extended nuclear deterrence. Roehrig is certainly aware of them, but perhaps he could have been more forceful in conveying how they are confusing and difficult for even experts to grasp.
The first quirk is that we do not have an understanding of how much nuclear weapons actually matter for nuclear deterrence. Of course, any suggestion that they do not matter would be ridiculous and oxymoronic. However, Roehrig acknowledges that the conventional military might that the United States can bring to bear can help generate confidence that the nuclear umbrella is working. He argues that Washington may not even have to respond in kind to a nuclear strike in order to certify the umbrella. And indeed, as mentioned, conventional military deployments demonstrate “skin-in-the-game” and enhance local war-fighting capabilities. Yet Roehrig describes Japanese government officials enjoying their visits to nuclear-armed Ohio-class submarines and the Sandia National Laboratories—visits that made the abstract nature of nuclear deterrence much more tangible and vivid to them (109). In a world without nuclear weapons, what would be the effect that US treaty pledges and conventional deployments have for securing allies? Or is the question nonsensical since the United States overcame its long-standing resistance to entangling alliances and large standing armies only because of nuclear weapons?
The second quirk concerns whether nuclear deterrence is even happening. More pointedly, can we credit the lack of large-scale aggression against Japan and South Korea to the nuclear umbrella provided by the United States? Many debates about nuclear weapons and their political effects are hard to resolve since we simply lack the data to fully confirm or disconfirm hypotheses. Tus, this question is admittedly theological, but in reading this book one strains to imagine a scenario in which China would use nuclear weapons against Japan. Can Beijing credibly threaten to use them to assert its territorial claims in the East China Sea? If South Korea has already had for decades a military superior to that of its Northern counterpart, then is the threat of a retaliatory nuclear response by the United States really what is keeping North Korea from launching an invasion of the South? Some scholars have even thrown into question whether nuclear weapons have any coercive value beyond strategic deterrence: the use of nuclear weapons is unnecessary for most military objectives and extremely costly since it can provoke strong reprisals and condemnation (Todd S. Sechser and Matthew Fuhrmann, Nuclear Weapons and Coercive Diplomacy, Cambridge University Press, 2017). If true, then Chinese or North Korean efforts to engage in nuclear blackmail would fail. The extreme implication is that the nuclear umbrella might just be moot or even pointless. After all, Roehrig contends that nuclear deterrence only works for the severest forms of aggression (to the extent that China and North Korea would wish to undertake them)—that is, aggression that might already be prevented by way of conventional means (186).
I suspect these puzzles are near impossible to solve. Yet these very uncertainties are what make the study of nuclear weapons and alliance politics in international politics so fascinating. Terence Roehrig has done an admirable job in laying out the issues in their theoretical and historical context. Scholars and practitioners alike should draw on his analysis and dig deeper into what makes extended nuclear deterrence truly tick.
Alexander Lanoszka
University of Waterloo, Waterloo, Canada